We will continue to examine nonmammalian species for evidence of Event Related Potentials (ERPs) under the paradigms of stimulation that cause cognitive events (thoughts) and waves in humans. Selected species will be tested with many recording semimicroelectrodes chronically placed on or in the brain. Stimulus situations include (i) omitted stimuli in a monotonous series, (ii) "oddball' stimuli of low probability in such a series, including ethologically significant ones, (iii) "mismatch" stimuli, overlapping with the foregoing, (iv) reinforced paradigms used for Contingent Negative Variation (CNV) and discriminant P300-like waves, and (v) for favorable species, tailored to their ethology, incongruous termination of an expected sequence such as bird calls slightly altered from the normal. The variables to be examined, for each of the waves discovered are (a) the form, polarity and time course under various stimulus conditions, (b) alterations in dynamics with stimulus repetition and temporal pattern, (c) distribution among parts of the brain, including subcortical and brainstem levels and the retina, (d) distribution among phyla and classes of animals, including especially elasmobranchs, teleost fish and reptiles, but also cephalopods and birds, (e) behavioral and brain variables chosen to estimate the degree to which waves are sensitive to changes in state (endogenic). Finding, validating and characterizing model species among lower animals is regarded as a necessary antecedent to assessing the behavioral and cognitive significance of ERPs and to the future use of lower species for analytical physiology, anatomy and pharmacology of these waves.